924Board.org

462avi · Posted: Fri Apr 27, 2007 1:46 pm Post subject: cgt specs

Does anyone have the engine specs for the 924 cgt. Info like, timing settings, cam info, rpm at which the turbo starts producing boost. I know it is a strange request but I replaced my turbo with a cgt turbo and I want to make sure that all of the settings are correct. Like if I need a different cam or distributor etc. My boost appear to roll on at like 3500 rpm and lasts through redline but up until the boost rolls on the car is a dog. It passes smog and appears to be operating normally.

Thanks
Geoff
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2005 C230K
2002 grand cherokee with 4.7L

ic932 · Joined: 11 Feb 2005 Posts: 1104 Location: UK

IIRC, the cam is identical to the 931, but went through a hardening process. Compression is 8.5.1 same as RoW S2's.

Like the S2 models the CGT had digital ignition so the distributer plays no role in timing issues. It merely has to be installed correctly, the DITC adjusts the ignition timing depending on boost levels.

The turbo should kick in earlier than 3,500 though, i would of thought?

What pistons are you using Geoff ?

462avi · Posted: Sat Apr 28, 2007 1:27 am Post subject:

Its a 1980 U.S. spec 931. It is running 7.5:1 c/r. The distributor on this car is the old vacuum style, no electronics at all. Here is basically what I am seeing. I have a boost/vacuum gauge installed in the dash. I see 20 in/hg at idle as I accelerate I see the boost start to overcome the vacuum at about 2000 rpm. After 2500 rpm the boost starts to show on the pressure side of the gauge and I have all 7 psi at just alittle over 3500 rpm. I was thinking that maybe I need to advance the timing alittle more. This car is set to the stock timing settings. So 6-9 btdc at idle and about 38 btdc at wot. I am thinking that the cgt turbo may need more exhaust pressure to turn it effectively.

Geoff
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2005 C230K
2002 grand cherokee with 4.7L

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11733 Location: PacNW

What is a CGT Turbo, exactly? PET doesn't seem to show anything different.
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Toofah King Bad

WeiBe (1987 924S 2.5t) - 931 S3

462avi · Posted: Sat Apr 28, 2007 1:43 pm Post subject:

Its the hot side that is different. The inducer is the same but the exducer is different, it is larger. As far as I can deduce what this all e up meaning is that it should spool later in the rpm range thus lasting longer in the upper rpm ranges. It appears to do that but I don't know if the engine is performing to what the turbo is looking for. Granted the cgt ran at 10 psi and I indeed plan on raising the boost but only after installing an intercooler. My biggest problem is that the cgt was an anomaly there just was not a lot made and info is sparce, couple that with the fact that there is no off the shelf alternative to our turbos makes finding tuning info hard to find.

p.s. how are the seats?

Geoff
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2005 C230K
2002 grand cherokee with 4.7L

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11733 Location: PacNW

Seats are still sitting in the box at the office. . .waiting for my next move, which might be a trip up to Heritage Trim in Washington. . .still trying to figure that out!
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Toofah King Bad

WeiBe (1987 924S 2.5t) - 931 S3